Treatment of work with solvents



April 5, 1938. c. F. DlNl 'EY TREATMENT OF WORK WITH SOLVENTS Filed May15, 1934 3 Sheets-Sheet 1 INVENTOB:

WITNESSES:

TTORNEYS.

April 5, 1938. C DlNLEY I 2,113,129

TREATMENTOF WORK WITH SOLVENTS Filed y 15, 1954 5 Sheets-Sheet 2 9WITNESSES: 6 96 INVENTOR:

g/ Gill 2151166 75 175171691 Patented Apr. 5, 1938 s as PATENT IFFICEClarence F. Illnley, Detroit, Mich, assignor, by

mesne assignments, to Solvent Machine Company, trustee, Detroit, Mich, acorporation or Michigan Application May 15, 1934, Serial No. 725,133

work with solvents for such purposes as cleaning anddegreasing, and tothe use of volatile solvents; and especially to the cleaning of metalparts in preparation for plating. For the purposes of the invention,various solvents whose vapors are heavier than air are especiallyadvantageous, such as benzine, benzol, and chicrinated solvents likecarbon tetrachloride, trichloromethane, tetrachloromethane,.dichlorethane, tetrachlorethane, trichlorethylene, andtetrachlorethylene, whose vapors are uninfiammable. In thus cleaningsuch metal parts, it is commonly most advantageous to treat them mainlyin boiling liquid solvent, rather than in the solvent vapor, and tominimize the vapor layer above the liquid solvent as far as possible;although in some cases the work may be satisfactorily cleaned in thesolvent vapor, without immersion in liquid solvent or sprayingtherewith, orthe like. My novel apparatus for such workaccomplishes thetreatment in a very simple, compact, and convenient manner. In certainaspects my apparatus may be regarded as an improvement of that disclosedin my Patent No. 1,942,355, granted January 2, 1934.

In preparing metal parts for plating, their surfaces are buiied withstearic bumng compounds (comprising abrasive like pumice and rouge mixedwith grease such as tallow) ,-which reduces the unevenness of theirsurfaces,-and then precleaned. One way of precleaning is to dry-buff orcolor" the work: this, however, is laborious, and entails hand scrubbingto remove bufilng compound and lint from the crevices, if the work hasretentive crevices. Anothermethod of-. precleaning is by electro-alkali,cleaner, followed by hand scrubbing. Still another method is topreclean in a heated oleaginous solvent, like gasoline, benzine, etc.,and then in an electroalkali cleaner. This method involves considerableloss of solvent, and serious fire hazard, although in itself fairlysuccessful.

By precleaning with chlorinated solvents in accordance with myinvention, such operations as hand coloring and hand scrubbing areavoided, as well as the fire hazards of inflammable solvents likegasoline, benzine, etc. My method is also very economical, reducing theloss of solvent. When the chlorinated solvent is kept free of water andfairly clean, use of an electroalkali cleaner is unnecessary; but whenit becomes substantially contaminated with the matter removed from thework in cleaning, so that 65 contamination amounts to as much as 15% byvolume. the work must afterward be lightly cleaned in an electro-alkalicleaner. Even so, however, the time-required for the final electroalkalicleaning is greatly reduced, production can be increased, and there isconsiderable saving of electrical energy.

Using this last procedure, I have found that ii the work is nottransferred from the chlorine ated solvent treatment to theelectro-alkali cleaner right away, the residue left on its surface afterthe chlorinated solvent treatment tends to "set up, thus becoming harderto remove in the electro-alkali cleaner bath. This is because the waterof condensation, which unavoidably collects in a layer'on the top of thechlorinated solvent bath, water-spots the work.

However, I have discovered that by a small protective addition to thechlorinated solvent bath, as of fat like lard or tallow, this can beovercome: i. e., the lard or tallow coats the work cleaned in the bathof boiling chlorinated solvent in'a very thin film, and the water on thebath cannot penetrate this film and spot the Fig. III is a side view ofanother form of apparatus, partly'in vertical mid-section.

Fig. IV is a plan view of the apparatus shown in Fig. III.

Fig. V shows a, horizontal section taken as indicated by the line andarrows VV in Fig. III; and.

Fig. VI is a fragmentary sectional view on a larger scale than Figs.III-V, taken as indicated by the line and arrows VI-VI in Fig. IV.

The apparatus shown in Figs. I and II comprises a treating vessel orenclosure I 0 open upward for the introduction and removal of the thingsor work to be treated, but closed to exclude air and retain the solventvapor. The enclosure or casing l0 forms a tunnel-like chamber withupward sloping entrance and exit ends I I and i2, and an approximatelyhorizontal midbody l3; and its lower portion serves as a tank or vat forthe liquidsolvent. Along the upper portion of the casing i0 is an(overhead) conveyor 15 for the articles or work, which conveyor I5 is'here shown as comprising a tworail track l6, l6, (of angle sections)and a plurality oi double-roller trolley carriers l1, provided withsupporting means such as trays I3, for carrying the articles or workthrough the treating chamber l0. Means may be provided for moving thetrolleys I! along the track l6 at suitable intervals, such as a conveyorchain 20, some of whose links may be pivoted together by the trolleyroller axes or spindles 2|. The conveyor l5 may in practice form part ofthe general conveyor system of a plant or plantdepartment where theapparatus is used. At the upward-sloping open casing ends ll, l2, thetrack l6, l5 likewise bends and slopes upward. Between the end openingsat ll, l2, the casing top or r001 22 is closed except for a longitudinaltrolley slot 23 between the angle tracks l5, N, which are secured toupturned roof flanges 24, 24 that coact with said angles i3, IE to forma sort of monitor structure.

The lower mid-portion l3 oi. the casing l5 has means for heating andvaporizing (boiling) the solvent, such as longitudinal steam pipes 25,25 at either side thereof, below the path or sweep of the conveyorcarriers H. The heating means 25, 25 are high enough above the bottom ofthe vessel at ill to afford a relatively tranquil settling zone or sumptherebeneath for dirt, lint, or other matter from the work. As shown,the lower portion of the vessel III is contracted, with inward slopingside walls at 26, 25, to form a reduced longitudinal trough-like sump 21for the sediment between the heating pipes 25, 25, which overlie thesloping bottom shoulders 26, 25. Separate provision is made for heatingthe contents of the settling zone or sump 21, as by means of a steamjacket 23 on its bottom wall. The sump 21 has a drainage outlet from itslow point, controlled by a valve 29.

Accumulation of vapor in theapparatus to the point of overflow or escapefrom the open tunnel ends at H, i2 and from the trolley slot 23 in theroof 22 may be prevented by condensing the vapor. As shown in Fig. II,part at least of the condensing means may be interposed between the workon the carriers I1 and the outer opening of the roof-slot 23, so as toprevent access of solvent vapor to the slot 23. In the present instance,there are two thin fiat cold-water Jacket sections or units 30, 30, atopposite sides of the trolley shanks" which extend up through the slot23 and travel therein. The condensers 30, 30 need not be right upagainst the r001 22, but may (as here shown) be as low down in thecasing III as consists with their clearing the work on the carriers IT.The condenser sections 30, 30 may be supported and secured on brackets3|, 3| fixed to the casing sides, and may slope outward toward thesides. Collecting troughs 32, 32 are mounted on the casing sides underthe outer lower edges of the sections 33, 30, to catch the drippingcondensate. As shown, there are drain pipes 33 from the low points ofthe troughs 32,

controlled by valves 34, and delivering into (external) liquid storagetanks 35 at either side of the apparatus. Thus the purified condensateis collected by the troughs 32, 32 separate from the solvent heated bythe pipes 25, in which work has been cleaned, and can be stored and keptclean in the tanks 35. From these tanks 35. the solvent may be returnedto the lower portionot the apparatus through pipes 35 controlled byvalves 31.

A mode of operation of this form of apparatus is as follows:

It work is to be cleaned by immersion in hot liquid solvent, theapparatus is filled with liquid solvent about up to the level I, aboutlard or tallow or the like being preferably added to the solvent.'I'he'valve 29 is, of course, closed. The heating pipes 25, 25 aresupplied with steam, while cold water is circulated through the coolingunits 30, 30. No steam or heat is supplied to the Jacket 28. The valves29, 34, 31 are closed. The liquid solvent is heated, by the pipes 25,25, and kept at asuitable temperature for cleaning the work. The vaporthus evolved is condensed by the cooling units 30, 30, and thus keptfrom rising above them, and from reaching the openings at H, I 2 and 23.When the liquid solvent is hot enough, work may be passed through it onthe carriers I! by means of the conveyor system l5, and cleaned by thesolvent and washing action of the liquid. Grease and oil dissolve in thesolvent, while solid particles of grit, buiilng compounds, lint, or thelike wash of! and settle by gravity into the tranquil region or zonebelow the heating pipes 25, 25,.where the liquid is not boiling or beingagitated by the heat. Thus such matter is kept out of the liquidcirculation in the vessel at ill, and has no chance to settle on thecleaned work, or to come in contact with it and adhere to it. Thesolvent vapor condensed by the condensers 30 runs down into the troughs32 and overfiows back into the pool of hot solvent in the vessell0,--the valves 34 being closed.

It the work is to be cleaned with solvent vapor instead 01 by contactwith liquid solvent, then the solvent level will be about at I, justbelow the carrier trays l3.

When dirt and grease have accumulated in the apparatus up to the pipes25, or as much as deemed desirable, the passage of work therethrough isstopped, and the valves 34 are opened,-the valves 23 and 31 stillremaining closed. The supplies of steam and of condensing water beingcontinued, and hotter steam supplied if necessary, the solvent boils,and condensate from the troughs 32 drains into the storage tanks 35,-until all the solvent in the apparatus has been thus purified and storedin these tanks,excepting, of course, that below the heating pipes 25.Thereupon steam may be shut-oil! from the pipes 25 and turned into thebottom jacket 23; and thus the distillation of solvent may be continuedand completed. when all the solvent (or as much as desired) has thusbeen purified, the steam (and cooling water) supply may be shut-oi!altogether, and the drain valve 29 may be opened to draw of! theaccumulated sludge of oil, grease, and dirt from the sump 21. Itdesired, 0! course, a certain amount of solvent may be left in thissludge, to make it liquid enough to be drawn ofl. easily; and in thiscase it may not always be necessary to use the heating jacket 23. Thesump 21 and the interior oi the A apparatus may. course, be furthercleaned mechanically, or washed out with any suitable solvent or otherfluid. As shown in Fig. II, the solvent return pipes 36 from storagetanks 35 open into the vessel i0 above the settling zone in its lowerportion, so that.purified condensate from the tanks may be used forwashing out the settling zone. Thereafter the valve 23 is closed, andthe valves 31 are opened to return the purified solvent into theapparatusywhereupon the valves 34 and 31 are all closed; and theapparatus is ready to restart operation as already described.

The apparatus shown in Figs. III-VI com- 1 5|, 52, but ofls'et outwardand inward from them,

respectively. The apparatus may preferably have a removable cover or lid'50 over its top, shown as a metal plate whose margin engages an angleflange lip 59 on an outer upper shell wall 60, extending above thejacket 56. In the cover 58 there may be a charging or loading andunloading opening H, for the introduction and removal of work into andfrom the vat 50. Work may be carried along in a closed circuit throughthe vat 50 by a moving conveyor or carrier 62, preferably mounted on thecover 50 and removable with it.

The particular apparatus here illustrated is of a circular design; itsvat or chamber 50 is of an annular configuration; and its workrconveyoror carrier 62 revolves as a turntable. This revolving carrier orturntable 62 is mounted on the lower end of an upright shaft 63 whichextends up into an upper Journal bearing .64 on the cover 50, and downinto a lower step bearing 65 mounted on angle bars 66 fixed across theinterior of the inner shell 52. The carrier 62 comprises an angle barrim 6'! and a diametrally extending channel 60 to which iswelded thecarrier hub 69, and whose ends are attached to angle bar chords I0, 10,whose ends are in turn fastened to the rim 61. The carrier 62 maybedriven by an (electric) motor I3 mounted on the cover 56- and connectedby a variable speed belt drive I4 and a worm reduction gearing 15 to anupright shaft 16 which extends down through the cover 50 to a spurpinion Il meshing with a spur gear 78 on the carrier shaft 53, betweenthecarrier and the cover.

In the apparatus, the work may be supported I by removable plating racks00 whose supporting -hooks 8i take into holes in the horizontal legs ofangle brackets or stirrups 82 adjustably secured to the outer angle-rim61 of the carrier 62 by screws 61a extend ing through vertical slots 61bin the upright bracket legs, and taking into the rim 61. Racks 00 withtheir charges of articles to be plated may be hung on the carrierstirrups 82 and removed, one by one, as the stirrups 02 pass adjacent(beneath) the opening 6i. As

indicated in Figs. III and IV, each rack 00 com- Q prises a verticalseries ofhorizontal bars 05 mounted on an upright center rod 86, andprovided with plating hooks 8?. The rod 06 has a hook 853 at its upperend, by which the rack can be handled-as well as the supporting hook 8ialready mentioned.

Forheating the liquid solvent in vat 50 in ordi-, nary operation, thereare a couple of annular steam pipes 90, 9! coiled around the vat at asufiicient height above its bottom to allow a settling zone below formatter from the work. These pipes 90, have steam supply connections 92,99 at the rear of the apparatus (Fig. V), and also discharge connections90, 95. For heating the contents of the vat 50 when below the level ofthe coils 90, 9| (for cleaning out purposes), the vat has a steam jacket96 on its bottom, with stays 91 thereacross for resisting the internalpressure. Steam is supplied to the jacket 96 through a pipe 98 thatextends about half carrier 62.

way around the jacket, where it terminates behind a baiiie 99. Water ofcondensation, etc., is discharged from the jacket 96 through a pipe I00.0

Cooling water is circulated through the annular cooling jackets 56, 51,for the purpose of chilling and condensing the solvent vapor evolvingfrom the hot liquid-solvent in the vat. For the outer jacket 56, thereare supply pipes IOI, I0I which enter the Jacket at diametricallyopposite points close to its bottom, and discharge pipes I02, I02 whichare connected to the jacket near its top, at diametrically oppositepoints midway between the pipes IOI, IOI. For the inner jacket 51, thereis-a supply pipe I03 entering the Jacket near its bottom and adiametrically opposite discharge pipe I04 connected to the jacket nearits top. These pipes I03, I04 extend down through the inner reservoir 54and out across through the vat 50 below the heating coils 90, 9|.

The solvent vapor condensing on the cool inner walls of the jackets 56,51 trickles down into annular collecting troughs I06, I01 between theupper margins oi the vat walls SI, 52 and the inner walls of thejackets. The bottoms of these troughs I06, I01 are formed by angle ringsI00, I09 afllxed to the inner and outer sides of the "vat walls 5I, .52,and the jackets 56, "51 are attached to the outer margins of theanglcs.- From the troughs I06, I01, the condensed solvent ordinarilydrains directly back into the vat 50 through holes H0, H0 in the troughwalls 5|, 52, which are ordinarily open, but can be closed by means ofscrew plugs III, II2 as shown In Fig. IV. When the holes IIO, IIO areclosed, the condensate can be drained from the troughs I06, I01 into theinner reservoir 54 through pipes H3, H4 controlled by valves H5, H6.From the reservoir 54, liquid solvent can be transferred or returned tovat 50 through a pipe line 'I II, which as here shown extends up abovethe jacket 56 and in through the upper (outer) shell wall 60, and hasinterposed therein a (hand) pump II8 for pumping the liquid solvent overinto the vat 50; a control valve H9; and a supply connection I20 with acontrol valve I2I. As here shown, one of the drain pipes H4 takes intothe lower portion of the pipe line I, so that the latter performs adouble function.

In the outer vat wall 5|, there may be one or more clean-out openingswith removable covers or doors I22 secured thereto with fluid-tightjoints.

In ordinary operation, thellquid solvent in the vat 50, standing aboutatthe level L and containing about of lard or tallow, or the like, ifdesired, is heated by the steam coils 90, 96, and kept at a suitabletemperature for cleaning the work. The carrier 62 is driven by the motor13 (through the change speed and reduction gearing I4, 15) at anysuitable rate, such as /2 to 1% R. P. M., and the racks 80, previouslycharged with-articles to be cleaned, are loaded. on the carrier andunloaded therefrom as the carrier stirrups 82 pass the cover opening 6I. Between loading and unloading, each rack 80 may make one fullrevolution (or more) with the The hot solvent drains and drys from thehot articles almost immediately as each plating rack 80 is removed fromthe machine. and the articles remain on the plating racks hot and dry,ready for plating.

The solid residues of, dirtremoved from the articles by the solvent,such as lint, grit, bufllng compound, settle to the bottom of the vat50,

below the coils 90, 9!. When the accumulation of such solids reaches thecoils, cleaning of the apparatus and of the solvent is advisable,-sincethe solvent has also become contaminated by the grease dissolved fromthe articles cleaned. For this purpose, after steam has been temporarilyshut oil from the coils 90, 9|, the drain holes H0, H0 are closed withthe plugs ill, H2, and the valves H5, H6 in pipes H3, H4 are opened, toallow the purified condensate to drain from troughs I06, I01 intoreservoir 54. Steam having been re-admitted to the coils 90, 9|, solventis distilled over into the reservoir 54 till its surface comes down tothe coils,-when, if desired, steam is shut off from them and admited tobottom Jacket 96, and distillation continued till substantially allsolvent has been distilled over. Then clean-out door(s) I22 are opened,and the residue of oil, buillng compound, lint, etc. is removed from thebottom 01' the vat. The apparatus may then be restored to ordinaryoperating condition (as explained above), the purified solvent pumpedback from reservoir 54 into vat 50, and loss of solvent made up byaddition oi fresh solvent, through cover opening 6| or connection H0.

Having thus described my invention, I claim:

1. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vessel or vat provided with means of drainage from its bottom,heating means for heating the liquid solvent therein located high enoughabove the bottom of the vessel to afford a settling zone for matter fromthe work below said heating means, condensing means at a higher level ofthe vessel for condensing solvent vapor evolved therein, means forcollecting and means for storing the condensate, and returning thestored condensate to said vessel above its said settling zone, so thatthe purified condensate may be used for washing out said zone.

2. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vessel or vat having a contracted lower portion or sump providedwith means of drainage at its bottom, heating means in the vessellocated'above and aside from said sump high enough above the bottom ofthe vessel to afford a settling zone for matter from the work below saidheating means, condensing means at a higher level of the vessel forcondensing solvent vapor evolved therein, means for collecting andstoring the condensate, and means for returning the stored condensate tosaid vessel above its said sump, so that the purified condensate may beused for washing out said sump.

3. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vessel or vat having a contracted lower portion or sump providedwith means of drainage at its bottom, heating means for heating theliquid solvent in the vessel above said sump, con-- densing means at ahigher level of the vessel for condensing solvent vapor evolved therein,means for collecting and storing the condensate, means for returning thestored condensate to said vessel above its said sump, so that thepurified condensate may be used for washing out said sump and means forheating the contents of said sump.

4. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vessel or vat having a contracted lower portion or sump, heatingmeans for heating the liquid solvent in the vessel located above andaside from said sump, condensing means at a higher level of the vesselfor condensing solvent vapor evolved therein, and means for heating thecontents of said sump.

5. In apparatus of the character described, for treating things or worktherein with volatile solvent whose vapor is heavier than air, thecombination of a treating vessel or chamber closed and covered over toexclude air and retain the solvent vapor, but open at its upper portionfor the introduction and removal of work and also having a conveyor slotin its roof, an overhead conveyor supported above said slot andincluding means extending down through the slot and adapted to traveltherein to carry work through the chamber, and condensing meansextending along at either side of the path of said downward-extendingmeans and interposed between the opening of said slot and the workcarried by the conveyor, and preventing access of the solvent vapor tosaid slot.

6. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vat extending around an inner space, a cover therefor aperturedfor the introduction and removal of work into and from the vat, a movingcarrier beneath the cover for the work in the vat, passing under thecover opening for loading and unloading therethrough, heating means forboiling the solvent in the vat located below the sweep of the carrierbut high enough above the bottom of the vat to afi'ord a settling zonefor matter from the work below said heating means, condensing means at ahigher level of ing and unloading therethrough, and condensing means forthe solvent vapor in the central space to the inside of the vat belowthe cover.

8. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vat extending around a central space, a cover therefor aperturedfor the introduction and removal of work into and from the vat, a movingcarrier beneath the cover for the work in the vat, passing adjacent thecover opening for loading and unloading therethrough, and condensingmeans for the solvent vapor in the central space within and below thesweep of said moving carrier.

9. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vat extending around a central space, a cover therefor aperturedfor the introduction and removal of work into and from the vat, a movingcarrier beneath the cover for the work in the vat, passing adjacent thecover opening for loading and unloading therethrough, condensing meansfor the solvent vapor in the central space to the inside of the vatbelow the cover, and condensing means at the outer side of the vat atsaid cover opening.

10. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent vat extending around a central space, a cover therefor aperturedfor the introduction and removal of work into and from the vat, a movingcarrier beneath the cover for the work in the vat, passing adjacent thecover opening for loading and unloading therethrough, condensing meansfor the solvent vapor in the central space within and below the sweep ofsaid moving carrier, and condensing means above the vat at said coveropening, outside the sweep of said moving carrier.

11. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent reservoir and a circumjacent solvent vat with outer wall higherthan its inner wall,-a cover over said vat and reservoir apertured forthe introduction and removal of work into and from the vat, a movingcarrier beneath the cover for the work in the vat, passing adjacent thecover opening for loading and unloading therethrough, and means forcondensing, below the cover but above the reservoir, the solvent vaporevolving from the vat, with drainage of the condensate into saidreservoir.

12. Apparatus of the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent reservoir and a circumjacent solvent vat with outer wall higherthan its inner wall, a cover over said vat and reservoir apertured forthe introduction and removal of work into and from the vat, means forcondensing, belowthe cover condensed solvent from said reservoir backinto the vat.

13. Apparatus oi the character described, for treating articles or workwith volatile solvent whose vapor is heavier than air, comprising asolvent reservoir and a circumjacent solvent vat with outer wall higherthan its inner wall, a removable cover over said vat and reservoir, amoving carrier for the work in the vat mounted on the cover at its lowerside and removable with and by the cover, means for condensing below thecover the solvent vapor evolving from the vat. with drainage of thecondensate into said reservoir, and means for pumping the condensedsolvent from said reservoir back into the vat.

14. A method 0!. cleaning articles or work in a vessel with volatilesolvent whose vapor is heavier than air, accumulating matter from thework in the vessel while avoiding contamination of work with theaccumulated matter, and periodically distilling the used solvent.allowing the vessel to be cleaned out, and recovering the solvent freeof the accumulated matter; which method comprises heating and vaporizingthe liquid solvent in the vessel at a zone or level sufllciently abovethe bottom of the vessel, during the ordinaryoperation of cleaning thework, to provide a tranquil settling zone tor the accumulation 0! matterirom the work in the lower portion of the vessel, while condensing thesolvent vapor evolved by the heating of the solvent at a higher level ofthe vessel than said heating zone; cleaning work in the vessel, whilematter therefrom accumulates in the settling zone; and as theaccumulation of settled matter substantially reaches the heating zone,discontinuing the cleaning of work anddistilling of! the solvent fromsaid settling zone: while condensing the solvent vapor evolved andcollecting and storing the purifled liquid condensate separate from theused liquid solvent in the vessel, continuing the distillation until theused liquid solvent is boiled away, and then discontinuing thedistillation and removing the residue from the vessel.

CLARENCE F. DINLEY.

